The RingBuf caches the last value it read of the producer so it doesn't
need to constantly contend on the actual producer cache line if lots of
messages have yet to be consumed. It was bogus to initialize this cache
at 0. This patch initializes it properly and adds testing.
Fixes: #1309
This commit extends the EbpfLoader with set_map_pin_path that allows the
caller to associate a named map with a pin path.
One note is that this path is an absolute path, not relative to
`map_pin_path`, and it forces the map to be loaded from that path.
This is the path in which pinned maps are created or resolved. It
isn't actually the path for any specific map itself. This rename
makes way for a method `set_map_pin_path` that actually specifies
the pin path for a specific map.
Add guardrails for when setting event type and config for perf_event
programs. The `PerfEventConfig` enum now defines the event `type` and
`config` of interest.
Remove public re-exports, and add idiomatic Rust types for:
- perf_hw_id => HardwareEvent
- perf_sw_ids => SoftwareEvent
- perf_hw_cache_id => HwCacheEvent
- perf_hw_cache_op_id => HwCacheOp
- perf_hw_cache_op_result_id => HwCacheResult
The motivation behind this is mainly for the `type` and `config` fields
of `bpf_link_info.perf_event.event`. The newly added enums are planned
to also be used in the `bpf_link_info` metadata.
Although `Breakpoint`/`PERF_TYPE_BREAKPOINT` variant exists, it is not
fully implemented. It's only usage at the moment is in link info.
`git submodule update` fails when running in a codex sandbox:
```
error: could not lock config file /Users/tamird/src/aya/.git/modules/libbpf/config: Operation not permitted
```
so just avoid it when not necessary.